The present invention is related to an improved adjustable wrench which enables a user to continuously conveniently wrench a polygonal bolt head or nut at one time without troublesome operation.
An adjustable wrench is generally used to wrench a nut or a bolt with a polygonal head section. A user often needs to repeatedly fit the wrench onto the bolt to wrench the same and then unfit the wrench from the bolt and then refit the wrench onto the bolt to further wrench the bolt until the bolt is tightened. Such procedure is quite troublesome. An improved adjustable wrench has been developed to overcome the above problem. The handle of the improved adjustable wrench can be conveniently reciprocally swung as a ratchet wrench to quickly tighten or untighten a bolt or a nut.
FIG. 4 shows a conventional adjustable wrench. The front end of the handle 8 of the wrench is forked to have two diverging sheets 81 spaced from each other by a gap 82. A sector section 831 of a fixed jaw 83 is pivotally disposed in the gap 82 via a pivot shaft 84. A fulcrum is defined between the front end of the handle 8 and the fixed jaw 83. An abutting pin 85 is arranged at the two sheets 81. By means of adjusting the position of the abutting pin 85, the fixed jaw 83 can be resiliently stretched or retracted about the fulcrum within the gap 82. Accordingly, when using the wrench, it is no more necessary for a user to repeatedly fit the wrench onto the polygonal head 9 of the bolt and unfit the wrench from the polygonal head 9. Instead, the user can reversely swing the handle 8 to instantaneously expand the clamping area 861 between the fixed jaw 83 and the movable jaw 86. Therefore, the wrench can be continuously operated to conveniently wrench the polygonal head 9 of the bolt. In addition, when the user desires to discharge the adjustable wrench from the one-way wrenching function as the ratchet wrench, the user only needs to move the abutting pin 85 to its home position to fix the fixed jaw 83 with the handle 8. Under such circumstance, the adjustable wrench can be operated in the original mode.
However, in order to achieve both the traditional function and the ratchet wrench-type function, the above adjustable wrench has numerous complicated components. For example, each of the two sheets 81 is formed with a slide slot 811. A wall of one of the slide slots 811 is further formed with cavity 812 in which a spring 813 and a ball member 814 are accommodated. A restricting block 832 protrudes from the arced edge of the sector section 831 of the fixed jaw 82. In addition, the sector section 831 is formed with a guide slot 833 along the arced edge. A stopper pin 834 is positioned in the guide slot 833 and inserted through the two sheets 81. A resilient member 835 is also positioned in the guide slot 833, whereby by means of the stopper pin 834 and the resilient member 835, the fixed jaw 83 can be reciprocally moved in an arced path. It is troublesome to assemble all these components of the wrench. Also, it is hard to manufacture these components. Moreover, in the case of damage of any of these components, the entire wrench will become useless.